Fastener driving machine

ABSTRACT

A fastener driving machine is adapted shown having a housing with a piston movable therewithin. An air pressure system is to move the piston in a driving stroke and a bumper is abuttable with the piston at the end of the driving stroke. An air return chamber is connected to the housing by means of a plurality of openings within the housing and these openings are normally below the piston at the time that the piston commences its return stroke. These openings will be above the piston if the bumper is damaged and, therefore, will not permit the machine to operate in this condition.

United States Patent Inventor Garry R. Perkins Rolling Meadows, Ill. 843,942

July 23, 1969 Mar. 9, I971 Spotnails, Inc.

Long Island, NY.

Appl. No. Filed Patented Assignee FASTEN ER DRIVING MACHINE 12 Claims, 5 Drawing Figs.

US. Cl. Int. Cl. Field of Search References Cited UNITED STATES PATENTS 3,353,737 11/1967 Howardetal.

3,496,840 2/1970 Wandel et al 227/130X 3,278,105 10/1966 Juilfs et al 227/130 3,278,106 10/1966 Becht et al 227/8 Primary Examiner-Granville Y. Custer, Jr. Attorney-4. Walton Bader ABSTRACT: A fastener driving machine is adapted shown I having a housing with a piston movable therewithin. An air pressure system is to move the piston in a driving stroke and a bumper is abuttable with the piston at the end of the driving stroke. An air return chamber is connected to the housing by means of a plurality of openings within the housing and these openings are normally below the piston at the time that the piston commences its return stroke. These openings will be above the piston if the bumper is damaged and, therefore, will not permit the machine to operate in this condition.

PATENTED MAR 9197! SHEET 1 OF 2 INVENTOR. Garry R. Perkins BY J- 1M Attorney DESCRIPTION OF THE INVENTION This invention relates to a fastener driving machine having a number of novel features.

The conventional fluid-operated fastener driving machine consists of a housingand a piston reciprocatingly movable within the housing. The piston is controlled by means of impingement of pressure air thereupon which is brought into impingement with the piston by means of valve structure. Other valve structure is provided in order to return the piston after the completion of the driving stroke. Since the driving stroke of the piston is produced by impingement of considerable force thereupon a resilient bumper is provided to cushion the shock.

It happens, in various operations, that the bumper, because of the considerable impact that has been placed against it, will fail. The bumper is, of course, normally invisible to the operator of the machine. Hence the machine is operated, in many cases, when the bumper has already failed.

The cost of replacement of a bumper is relatively minor but, if the bumper is not replaced after failure, the tool will be seriously damaged. The piston itself will impinge against the housing thereby destroying both the piston andthe housing. The cost of replacement of the piston is, of course, considerably greater than the replacement of the bumper and, if the housing is damaged, the tool itself must be replaced.

One of the objects of this invention is to provide a system which will automatically prevent the tool from operating if the bumper is damaged.

A further object of this invention is, at the same time that the safety feature involved herein is provided, to produce an air return system which will be simple and foolproof in opera tion.

Another object of this invention is to provide a tool of extremely compact construction because the air return system involved is carried by the magazine.

Another object of this invention is to provide a safety mechanism which is simple and foolproof in operation and is inexpensive to manufacture.

The above constitutes a brief description of this invention and some of the objects and advantages thereof. Other objects and advantages of this invention will become apparent to the reader of thisspecification as this description proceeds.

The invention will now be described by reference to the foregoing drawings which are made a part of this specification.

FIG. 1 is a front elevational view, partly in section, showing a fastener driving machine containing the improvements of this invention.

FIG. 2 is an enlarged detail sectional view of the safety mechanism utilized in the fastener driving machine of this invention. In this PIG. the manually actuated trigger has been depressed by the control valve plunger will not operate.

FIG. Zais a view similar to that of FIG. 2 but showing the position of the parts when the safety trigger and manually operated trigger are both depressed.

FIG. 3 is a view similar to that of FIG. 2 but showing the parts in the normal rest position.

FIG. 4 is a cross-sectional view showing the valve plunger and associated parts taken along lines 44 of FIG. 2.

The invention will now be further described by reference to the specific form; thereof shown in the accompanying drawings. In this connection, however, the reader is cautioned to note that the specific form of this invention, as shown in the specification herein, is for illustrative purposes and for purposesfor example only. Various changes and modifications could obviously be made within the spirit and scope of this invention.

Now referring to the specific form of this invention as shown in the drawings for a detailed descriptipn thereof there is shown a fastener driving machine 11 which includes an outer casing 12 which contains a housing (cylinder) 13 therewithin. Within cylinder 13 a piston 14 is reciprocatingly movable. Piston 14 has an opening 15 therewithin through which a pin 16 is disposed. Pin 16 is in turn connected to driver blade 17. Piston 14 also bears a downwardly depending portion 18 which is adapted to fit within an opening 19 which is provided within bumper 20. Bumper 20 is made of a resilient material such as rubber and contains an additional opening 21 therewithin through which driver blade 17 passes. Opening 21 is not sealed with respect to the passage of air so that air may pass therethrough during the operation of this device as will be subsequently explained.

Within piston 14 a diagonal opening 22 is also provided whose function will be subsequently explained.

Housing 13 bears a plurality of spaced openings 23 therewithin and an additional plurality of spaced openings 24 which are downwardly spaced from openings 23 and are larger in diameter. Openings 23 and 24 are spaced about the periphery of housing 13.

Driver blade 17 fits within a slot 25 which is disposed within the forward portion of magazine 26. A. plurality of fasteners 27 are disposed within magazine 26 and are sequentially propelled into position to impinge with driver blade 17 by follower means 28.

An air return chamber 29 is carried by magazine 26 and openings 23 and 24 join the interior of housing 13 with air return chamber 29 Above housing 13 and within member 12 is a poppet valve member 30. Poppet valve 30 contains an opening 32 therewithin and is upwardly and downwardly movable within opening 31 disposed within member 12. Poppet valve 30 bears an upwardly extending portion 33' therewithin which portion carries a spring 34 normally biasing the valve in the downward position. A seal 35 is provided and an opening to atmosphere 36 is likewise provided.

Piston 14 is sealed within housing 13 by means of 0 rings 37 and poppet 30 is likewise sealed within chamber 31 by means of 0 rings 38 and 38a.

Pressure air chamber 39 is provided within member 12. Chamber 39 is connected to a source of pressure air through opening 40 and conduit 40a. Chamber 3 9 is under air pressure. In the normal rest position of the device pressure air is also present within chamber 31 and this pressure air reaches chamber 31 through conduit 41 which in turn is connected to chamber 42 which in turn is connected to conduit 42a which extends into chamber 400 and thus permits pressure air to proceed where desired.

In the normal rest position of the device valve plunger 43 is in the position shown in FIG. 3 and is sealed within chamber 42 by means of an 0 ring 44. Member 43 is maintained in the down position by means of spring 45. Member 43 can be selectively actuated either by link 49 (which is connected to a downwardly depending probe 50 which has a right-angle bend thereupon) or by a hand-operated trigger 47. However, either of these elements will not move valve stem 43 sufficiently in order to cause 0 ring 44 to pass the lower portion 50 of conduit 41. It is noted that trigger 47 is pivotally connected at 48 and member 49 is pivotally connected to member 50. Mem' bers 49 and 47 are slidably connected to one another at 51.

Also, as noted in FIG. 2a, simultaneous operation of members 47 and 49 will cause element 43 to move above port 52 and thus operate the device as will be subsequently explained. Also it is to be noted that member 43 bears flutes 46 thereupon so that below 0 ring 44 there are passages provided for the movement of pressure air leaving chamber 42.

With the foregoing specific description the operation of this invention can now be explained.

In order to operate the device it is necessary that member 50 be in contact with the work so as to move link 49 upwardly as shown in FIG. 2a. Trigger 47 may then be manually controlled to move valve member 43 in the position shown in FIG. 2a. At this point pressure air is no longer supplied through port 52 into conduit 41 but, instead, the pressure air contained in space 31 is being released to atmosphere through the flutes between elements 46. Since pressure air is always acting on the lower portion of poppet 30, poppet 30 then rises and seals against members 35 and 53 thereby permitting pressure air to impinge on piston 14. This causes piston 14 to move downwardly and rapidly and causes the lower portion of piston 14 to abut bumper 20. Since bumper 20 is resilient and is not of sufficient size to fill housing 13 completely, bumper 20 at the point of its initial contact with piston 14 is compressed and causes piston 14, for a short instant, to go below the level of openings 23. This permits pressure air to pass through openings 23 and into chamber 29. However, the resiliency of the bumper almost immediately thereafter, causes piston 14 to lie above the level openings 23. Pressure air also flows through opening 22 within piston 14 and enters chamber 29. This condition will continueuntil trigger 47 or, selectively link 49 is released and the valve stem 43 assumes the positions shown in FIGS. 2 and 3. At that point, of course, pressure air again flows through port 52 into conduit 41 and repressurizes space 31. This causes poppet 30 to assume the position shown in FIG. 1 and shuts off the supply of pressure air to the point above piston 14. However, since there is now pressure air in chamber 29 this pressure air applies a force to piston 14 and causes piston 14 to move upwardly. It is noted that additional openings 24 of larger diameter are provided which are in communication between housing 13 and chamber 29. This causes a more rapid release of pressure below piston 14 when the piston is to be returned. Normally, of course, when the trigger is depressed and pressure air is present above piston 14 there is a far greater volume of pressure air above this piston than below it and the piston remains.

in the down position.

it is also to be noted that air flowing through openings 24 will cool bumper 20 and prolong its life. Also some pressure air will flow through opening 21 and thus will prevent dirt from jamming the mechanism.

However, if bumper 20 is partially destroyed through use then piston 14 will remain below the levels of openings 23. This means, of course, that the pressure air contained in chamber 29 will act above piston 14 rather than below it. However, this pressure air will then exhaust through opening 32 and 36 to atmosphere. Thereby preventing the piston from returning. The operator of the device will, of course, immediately know, at that point, that something is wrong and will bring the device in for servicing for replacement of the bumper.

Also, in the normal operation of this device, pressure air will pass through opening 22 when piston 14 moves downwardly. This pressure air will act upon bumper 20 and will cause this bumper to be cooled, thereby improving the operation of the tool by causing the bumper to have longer life.

Also, as specifically shown in FIG. 2, 2a and 3 the movement of trigger 47 and link 49 slideable against one another at 51. This produces a smoother operation of the parts and permits more positive operation of the tool.

The foregoing sets forth the objects of this invention and the manner in which they are achieved.

lclaim:

1. A fastener driving machine comprising, in combination, a housing, a piston reciprocatingly movable within said housing, fastener driving means operatively connected to said piston, pressure air means selectively adapted to move said piston in a driving direction, resilient bumper means adapted to abut said piston at the end of said driving movement, an air return chamber, continuously open air passage means normally below said piston and joining said housing to said air return chamber, means permitting pressure air to enter said air return chamber during the driving stroke of said piston, said air passage means being closed by said piston at the time that the piston commences its return stroke but said passage means being opened if said bumper means are at least partially destroyed.

2. A fastener driving machine as described in claim 1 said passage means being a plurality of spaced openings connectinasaid housing with said air return chamber.

. A fastener driving machine as described in claim 2 including a second plurality of spaced openings connecting said housing and said air return chamber spaced below said first openings.

4. A fastener driving machine as described in claim 2 said second openings being larger than said first openings.

5. A fastener driving machine as described in claim 4 including an elongated magazine for storage of fasteners connected to said housing and fastener advancing means within said magazine, said magazine also carrying a portion of said air return chamber.

6. A fastener driving machine as described in claim 1 said opening being diagonally and outwardly extending.

7. A fastener driving machine as described in claim 6 said bumper provided with a cavity therewithin and said piston having a downwardly depending portion adapted to fit within said cavity when said piston and said bumper are in abutting w relationship.

8. A fastener driving machine as described in claim 3 said bumper means having a portion lying between said first and said second plurality of spaced openings.

9. A fastener driving machine as described in claim 5 said means permitting pressure air to enter said air return chamber during the driving movement of said piston comprising an opening provided within said piston.

10. A fastener driving machine as described in claim 7 said bumper being also provided with an inclined portion therein adjacent said second plurality of spaced openings.

11. A fastener driving machine as described in claim 1 said bumper provided with an inclined portion adjacent said air passage means.

12. A fastener driving machine as described in claim 5 said means permitting pressure air to enter said air return chamber during the driving movement of said piston comprising the resiliency of said bumper permitting said piston to pass below said first plurality of spaced openings. 

1. A fastener driving machine comprising, in combination, a housing, a piston reciprocatingly movable within said housing, fastener driving means operatively connected to said piston, pressure air means selectively adapted to move said piston in a driving direction, resilient bumper means adapted to abut said piston at the end of said driving movement, an air return chamber, continuously open air passage means normally below said piston and joining said housing to said air return chamber, means permitting pressure air to enter said air return chamber during the driving stroke of said piston, said air passage means being closed by said piston at the time that the piston commences its return stroke but said passage means being opened if said bumper means are at least partially destroyed.
 2. A fastener driving machine as described in claim 1 said passage means being a plurality of spaced openings connecting said housing with said air return chamber.
 3. A fastener driving machine as described in claim 2 including a second plurality of spaced openings connecting said housing and said air return chamber spaced below said first openings.
 4. A fastener driving machine as described in claim 2 said second openings being larger than said first openings.
 5. A fastener driving machine as described in claim 4 including an elongated magazine for storage of fasteners connected to said housing and fastener advancing means within said magazine, said magazine also carrying a portion of said air return chamber.
 6. A fastener driving machine as described in claim 1 said opening being diagonally and outwardly extending.
 7. A fastener driving machine as described in claim 6 said bumper provided with a cavity therewithin and said piston having a downwardly depending portion adapted to fit within said cavity when said piston and said bumper are in abutting relationship.
 8. A fastener driving machine as described in claim 3 said bumper means having a portion lying between said first and said second plurality of spaced openings.
 9. A fastener driving machine as described in claim 5 said means permitting pressure air to enter said air return chamber during the driving movement of said piston comprising an opening provided within said piston.
 10. A fastener driving machine as described in claim 7 said bumper being also provided with an inclined portion therein adjacent said second plurality of spaced openings.
 11. A fastener driving machine as described in claim 1 said bumper provided with an inclined portion adjacent said air passage means.
 12. A fastener driving machine as described in claim 5 said means permitting pressure air to enter said air return chamber during the driving movement of said piston comprising the resiliency of said bumper permitting said piston to pass below said first plurality of spaced openings. 